The province of Drenthe (the Netherlands) asked TNO whether switching off a large part of street lamps (according to the reorganization of public road lighting) as planned on the N386 will have negative consequences in terms of traffic safety or road user workload. In order to answer this question, a field study was conducted with the TNO instrumented vehicle during night time conditions. Thirty-two participants drove the road between Zuidlaren and Peize, once with the complete set of public lighting (as were originally present) and once with a restricted set of public lighting corresponding to the reorganisation plans. Driving behaviour (speed, standard deviation of speed, lateral position, swerving within the lane, braking behaviour and steering effort) were compared between the two lighting conditions, as well as subjective workload and answers to questionnaires. Participants did not know the actual purpose of the study. On trajectories on which a lot of street lamps were switched off, there was only one trajectory with a somewhat higher driving speed with all street lamps on. There was no difference in the standard deviation of the speed between the two lighting conditions. In the limited lighting condition, participants drove somewhat more to the right side of the road, but these results correspond to the behaviour found on the control location, so no extra risks are introduced due to lighting restrictions. The swerving was somewhat less with less road lighting. There were no differences in steering effort or in subjective workload. The questionnaires revealed some critical notes, such as the opinion that parts of the road were not well lit or that the roundabouts were not clearly designed. There were no or hardly any differences in remarks between the two lighting conditions. The general conclusion from this study is that in terms of driving behaviour, subjective experience and workload, there is no reason to assume that decreasing the number of street lamps according to the plans on the N386 increases safety risks compared to the current situation. It should be mentioned that this holds for the situation in which roundabouts and intersections are always lit and there are no cyclists on the road. For roads on which street lamps will also be removed on roundabouts and on intersections or for roads where cyclists are using the same carriageway, different conclusions may apply. (Author/publisher)
Abstract